README
¶
Mori
Mori finds functions that look alike, even when they are written in different programming languages.
Use it to find possible duplicate logic before you copy, refactor, or review code. Mori gives you a shortlist to inspect. It cannot prove that two functions do the same thing.
What It Does
Mori reads your source code locally and compares individual functions. It ignores details such as formatting, comments, most variable names, and literal values so it can focus on the shape of the code.
For example, it can flag a JavaScript function and a Go function that both:
- check an input;
- split it into parts;
- loop over those parts; and
- return early when something is wrong.
Each result includes a percentage and the code locations to review. A higher percentage means the functions have more structural overlap, not that they have identical behavior.
Install
Download a prebuilt binary for Linux, macOS, or Windows from the latest release.
Or install from source. You need Go 1.23 or newer and a C compiler.
go install github.com/Cyberlane/mori/cmd/mori@latest
mori version
Start Here
Run this from the root of a project:
mori scan --threshold 0.85 --min-tokens 40 .
This looks for reasonably sized functions that are very similar. Start at
0.85 to reduce noise. If you want more possible matches, lower the threshold
gradually.
To look only for matches between different languages:
mori scan --cross-language-only --threshold 0.65 .
To try Mori against this repository's example files:
mori scan --threshold 0.70 --cross-language-only examples/email-validation
Example output:
1. 71.0% structural similarity
A validator.js:1-4 [javascript] looksLikeEmail
B validator.go:5-8 [go] LooksLikeEmail
Read both functions before acting on a match. Mori does not understand runtime values, external calls, side effects, or all language-specific behavior.
Common Uses
Exclude test files:
mori scan --exclude '**/*_test.go' --exclude '**/*.test.ts' .
Write results as JSON for a script or CI system:
mori scan --format json .
Fail a CI job when Mori finds a match at your threshold:
mori scan --threshold 0.85 --fail-on-match .
With --fail-on-match, Mori exits with status 3 when it finds a match.
To record intentional candidates and use Mori as a stable CI gate:
mori baseline update --baseline mori-baseline.json --threshold 0.85 .
mori scan --baseline mori-baseline.json --threshold 0.85 --fail-on-match .
mori baseline prune --baseline mori-baseline.json --check .
baseline update accepts every candidate in the current untruncated scan, so
review its file diff before committing it. Baselines are opt-in, and a
suppressed candidate is reported in the scan summary. The conventional file
name is mori-baseline.json; pass it explicitly with --baseline.
Supported Languages
| Language | File types |
|---|---|
| Go | .go |
| JavaScript and JSX | .js, .jsx, .mjs, .cjs |
| TypeScript and TSX | .ts, .tsx, .mts, .cts |
| Python | .py, .pyi |
| Rust | .rs |
Run mori languages to see the languages in your installed version.
For AI Coding Tools
Mori includes an optional skill for compatible coding agents. It helps an agent use Mori results as review leads rather than treating a score as proof.
Install it in the current project:
mori skill install --project .
Install it for your user account instead:
mori skill install --global
More Detail
Development
make check
License
Mori is available under the MIT License.
Directories
¶
| Path | Synopsis |
|---|---|
|
cmd
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mori
command
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examples
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internal
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agentskill
Package agentskill installs Mori's embedded Agent Skill safely and deterministically.
|
Package agentskill installs Mori's embedded Agent Skill safely and deterministically. |
|
analyzer
Package analyzer orchestrates parsing, comparison, and deterministic results.
|
Package analyzer orchestrates parsing, comparison, and deterministic results. |
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baseline
Package baseline stores reviewed-and-accepted Mori match candidates.
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Package baseline stores reviewed-and-accepted Mori match candidates. |
|
buildinfo
Package buildinfo holds release metadata injected by linker flags or Go module build information.
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Package buildinfo holds release metadata injected by linker flags or Go module build information. |
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cli
Package cli implements the mori command-line interface.
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Package cli implements the mori command-line interface. |
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cmd/releasepack
command
Command releasepack creates one native release archive.
|
Command releasepack creates one native release archive. |
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cmd/skillpack
command
Command skillpack creates Mori's portable Agent Skill release archive.
|
Command skillpack creates Mori's portable Agent Skill release archive. |
|
diagnostic
Package diagnostic formats errors without exposing private filesystem paths.
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Package diagnostic formats errors without exposing private filesystem paths. |
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fingerprint
Package fingerprint creates stable content identities for normalized fragments and pairs of fragments.
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Package fingerprint creates stable content identities for normalized fragments and pairs of fragments. |
|
language
Package language owns supported Tree-sitter grammars and fragment boundaries.
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Package language owns supported Tree-sitter grammars and fragment boundaries. |
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model
Package model defines the analyzer's stable internal and output models.
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Package model defines the analyzer's stable internal and output models. |
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normalize
Package normalize converts grammar-specific trees into shared feature bags.
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Package normalize converts grammar-specific trees into shared feature bags. |
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parser
Package parser turns supported source files into normalized fragments.
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Package parser turns supported source files into normalized fragments. |
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release
Package release creates deterministic native release archives.
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Package release creates deterministic native release archives. |
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report
Package report renders stable machine-readable and human-readable reports.
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Package report renders stable machine-readable and human-readable reports. |
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similarity
Package similarity scores normalized AST feature bags.
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Package similarity scores normalized AST feature bags. |
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source
Package source discovers supported source files without following symlinks.
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Package source discovers supported source files without following symlinks. |
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Package skills embeds the official Agent Skills distributed with Mori.
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Package skills embeds the official Agent Skills distributed with Mori. |